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Save and restore GDT in UEFI loader. #3

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11 changes: 11 additions & 0 deletions uefi_loader/src/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,10 +10,14 @@ extern "C" {
#include <Protocol/LoadedImage.h>
#include <Protocol/MpService.h>
}
#include "zpp/scope_guard.h"
#include "zpp/x64/asm.h"
#include <cstddef>
#include <cstdint>
#include <string>

namespace zpp
{
/**
* The boot services.
*/
Expand Down Expand Up @@ -112,6 +116,11 @@ static int call_on_cpu(std::size_t cpuid,
{
int result = -1;

// Save this GDT and restore it at function exit.
alignas(0x10) unsigned char gdt_layout[0x10]{};
x64::sgdt(gdt_layout);
scope_guard restore_gdt = [&] { x64::lgdt(gdt_layout); };

// If this is the main CPU, just call the user function.
if (0 == cpuid) {
return function(context);
Expand Down Expand Up @@ -383,3 +392,5 @@ extern "C" EFI_STATUS EFIAPI uefi_main(EFI_HANDLE image_handle,
// Return success anyway, no image was found is considered ok.
return EFI_SUCCESS;
}

} // namespace zpp
8 changes: 4 additions & 4 deletions uefi_loader/uefi_loader.vcxproj
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Original file line number Diff line number Diff line change
Expand Up @@ -77,30 +77,30 @@
<NMakeCleanCommandLine>C:\Windows\sysnative\bash -c "make clean"</NMakeCleanCommandLine>
<NMakeReBuildCommandLine>C:\Windows\sysnative\bash -c "make clean &amp;&amp; make"</NMakeReBuildCommandLine>
<NMakePreprocessorDefinitions>WIN32;_DEBUG;$(NMakePreprocessorDefinitions)</NMakePreprocessorDefinitions>
<NMakeIncludeSearchPath>include;../loader/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
<NMakeIncludeSearchPath>include;../hypervisor/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
</PropertyGroup>
<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
<NMakeBuildCommandLine>C:\Windows\sysnative\bash -c make</NMakeBuildCommandLine>
<NMakeCleanCommandLine>C:\Windows\sysnative\bash -c "make clean"</NMakeCleanCommandLine>
<NMakeReBuildCommandLine>C:\Windows\sysnative\bash -c "make clean &amp;&amp; make"</NMakeReBuildCommandLine>
<NMakePreprocessorDefinitions>_DEBUG;$(NMakePreprocessorDefinitions)</NMakePreprocessorDefinitions>
<NMakeIncludeSearchPath>include;../loader/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
<NMakeIncludeSearchPath>include;../hypervisor/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
</PropertyGroup>
<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
<NMakeBuildCommandLine>C:\Windows\sysnative\bash -c "make mode=release"</NMakeBuildCommandLine>
<NMakeOutput>hypervisor.exe</NMakeOutput>
<NMakeCleanCommandLine>C:\Windows\sysnative\bash -c "make clean"</NMakeCleanCommandLine>
<NMakeReBuildCommandLine>C:\Windows\sysnative\bash -c "make clean &amp;&amp; make mode=release"</NMakeReBuildCommandLine>
<NMakePreprocessorDefinitions>WIN32;NDEBUG;$(NMakePreprocessorDefinitions)</NMakePreprocessorDefinitions>
<NMakeIncludeSearchPath>include;../loader/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
<NMakeIncludeSearchPath>include;../hypervisor/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
</PropertyGroup>
<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
<NMakeBuildCommandLine>C:\Windows\sysnative\bash -c "make mode=release"</NMakeBuildCommandLine>
<NMakeOutput>hypervisor.exe</NMakeOutput>
<NMakeCleanCommandLine>C:\Windows\sysnative\bash -c "make clean"</NMakeCleanCommandLine>
<NMakeReBuildCommandLine>C:\Windows\sysnative\bash -c "make clean &amp;&amp; make mode=release"</NMakeReBuildCommandLine>
<NMakePreprocessorDefinitions>NDEBUG;$(NMakePreprocessorDefinitions)</NMakePreprocessorDefinitions>
<NMakeIncludeSearchPath>include;../loader/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
<NMakeIncludeSearchPath>include;../hypervisor/include;C:/Temp/edk2-UDK2018/MdePkg/Include</NMakeIncludeSearchPath>
</PropertyGroup>
<ItemDefinitionGroup>
</ItemDefinitionGroup>
Expand Down